<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="../vue.global.js"></script>
  </head>
  <body>
    <div id="app">Counter: {{ counter }}</div>

    <script>
        const Root = {
            data(){
                return {
                    counter:0
                }
            },

            // 组件往DOM上挂载完毕后回调该函数
            mounted(){
                setInterval(
                    () => {
                        this.counter++
                    }, 
                    1000
                );
            }
        }
        Vue.createApp(Root).mount("#app")
    </script>
  </body>
</html>
